1. Field
Embodiments relate to a walking robot and a control method thereof.
2. Description of the Related Art
In general, when a walking robot walks on a rough plane or an inclined plane, such as stairs, or meets an obstacle, a bipedal walking robot has a greater degree of mobility than a wheeled robot. Particularly, since a walking robot may lose balance and then fall, consideration of stability is essential when walking patterns of the robot are set.
In order to assure dynamic stability of walking robots, research into generation of walking patterns in consideration of a zero moment point (ZMP) has been proposed.
The ZMP means a point where the sum of all moments caused by forces generated from soles of feet of a walking robot equals 0. That is, the ZMP is a point where the intensity of reaction between the feet of the robot and the ground becomes 0 on a contact plane between the feet and the ground. If the ZMP is located within a support plane where the soles of the feet and the ground contact each other, the robot may walk without falling.
Only if the ZMP is located within the contact plane between the soles of the feet and the ground whenever the walking robot moves when behavior patterns of the robot are generated, the robot stably maintains balance.
Recently, methods of maintain balance of walking robots mostly employ a technique in which a strategy for movement of joints to locate the ZMP within the support plane is established and an optimization problem to satisfy constraints is solved.
These methods have drawbacks, such as local minima in solving the optimization problem and long computation time. Further, these methods need to design a control strategy to maintain balance of a robot according to a model of the robot. Such a strategy is varied according to a target robot system to be controlled, and is not east to be organized in a common method.